800MPa级高强钢焊接粗晶区再热循环的组织转变规律
发布时间：2018-11-11 00:55
【摘要】：为了研究800MPa级低合金高强钢焊接粗晶区的组织转变规律,采用热模拟的方法,应用L78RITA相变热膨胀仪模拟了实验用钢的两次焊接热循环过程,对应的焊接线能量约为20kJ/cm。建立了该钢的奥氏体连续加热转变曲线(TTA),并对组织、硬度和热膨胀曲线进行分析,结果显示,实验用钢一次热循环粗晶区组织为板条马氏体和贝氏体,硬度为318HV,当第二次热循环峰值温度(Tp2)为1000℃时,第一次热循环后的组织发生完全重结晶,得到细小的贝氏体组织,硬度下降,当Tp2为900℃时发生部分重结晶,硬度最低(239HV),当Tp2为800℃时,在晶界和晶内相界生成链状分布的M-A组元,而Tp2小于A′c1时发生回火作用,M-A组元分解并析出碳化物。实验用钢的热影响区未出现组织遗传现象,因此为了更准确判断组织转变类型,应结合TTA曲线对焊接热影响区组织转变进行分析。
[Abstract]:In order to study the microstructure transformation of the coarse grain zone of 800MPa low alloy high strength steel, the thermal expansion process of two welding cycles of experimental steel was simulated by L78RITA phase transformation thermal expansion instrument. The corresponding welding line energy was about 20kJ / cm ~ (-1). The austenite continuous heating transformation curve (TTA),) was established and the microstructure, hardness and thermal expansion curves of the steel were analyzed. The results showed that the microstructure of the primary thermal cycle of the steel was lath martensite and bainite, and the hardness was 318HV. When the peak temperature of the second thermal cycle (Tp2) is 1000 鈩，
本文编号：2324052
[Abstract]:In order to study the microstructure transformation of the coarse grain zone of 800MPa low alloy high strength steel, the thermal expansion process of two welding cycles of experimental steel was simulated by L78RITA phase transformation thermal expansion instrument. The corresponding welding line energy was about 20kJ / cm ~ (-1). The austenite continuous heating transformation curve (TTA),) was established and the microstructure, hardness and thermal expansion curves of the steel were analyzed. The results showed that the microstructure of the primary thermal cycle of the steel was lath martensite and bainite, and the hardness was 318HV. When the peak temperature of the second thermal cycle (Tp2) is 1000 鈩，
本文编号：2324052
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